@trengriffin Well, how many rivers are there? If each one has a 500 flood every 500 years, how many such floods occur in a typical year globally?
@特伦格里芬嗯，有多少条河流？如果每500年发生一次500次洪水，那么全球每年有多少次这样的洪水？
@trengriffin Well, how many rivers are there? If each one has a 500 flood every 500 years, how many such floods occur in a typical year globally?
@特伦格里芬嗯，有多少条河流？如果每500年发生一次500次洪水，那么全球每年有多少次这样的洪水？